The instant invention relates to novel fire fighting concentrates which are derived from novel synergistic surfactant compositions and which upon dilution with fresh or sea water and aeration produce aqueous film forming foams capable of extinguishing non-polar and polar solvent and fuel fires.
Fire fighting foam concentrates which produce aqueous film forming foams are known a) as AFFF agents (for Aqueous Film Forming Foam) if they have the capability of extinguishing non-polar solvent or fuel fires and b) as AR-AFFF agents (for Alcohol Resistant AFFF agent) if they have the capability of extinguishing polar as well as non-polar solvent or fuel fires. Aqueous film forming foams are the most efficient fire fighting agents because they act in the following two ways as outlined in U.S. Pat. No. 4,472,286:
a) As aqueous foams they are used as primary fire extinguishing agents and PA1 b) As aqueous film formers they act as vapor supressors, augmenting the fire-extinguishing efficiency of the foam and preventing re-ignition of fuel or solvent vapors. PA1 R.sub.f is a straight or branched chain perfluoroalkyl group with 5 to 18 carbon atoms and preferably 5 to 13 carbon atoms; PA1 L.sub.1 is a bivalent linking group with 1 to 4 carbon atoms and preferably --CHF--(CH.sub.2).sub.2 -- and --(CH.sub.2).sub.3 --, PA1 R.sub.1 and R.sub.2 are alkyl or hydroxyalkyl with 1 to 4 carbon atoms or hydrogen with the proviso that only one of the R.sub.1 or R.sub.2 substituents can be hydrogen and the preferred R.sub.1 and R.sub.2 groups being methyl; PA1 Q.sup.- is --COO.sup.- or --SO.sub.3.sup.- and PA1 m is 1 to 4 and preferably 1 if Q.sup.- is --COO.sup.- and preferably 3 if Q.sup.- is --SO.sub.3.sup.-. PA1 R is either R.sub.f or R.sub.h and R.sub.f is a straight or branched chain perfluoroalkyl group with 3 to 18 carbon atoms and preferably 6 to 12 carbon atoms, R.sub.h is a straight or branched alkyl, alkenyl, cycloalkanyl or cycloparaffin group with 6 to 18 carbon atoms and preferably an alkyl group with 8 to 12 carbon atoms and PA1 L.sub.2 is either zero or a bivalent linking group and PA1 Q.sub.2 is either --SO.sub.3 M or --OSO.sub.3 M and preferably --OSO.sub.3 M if R is R.sub.h and --SO.sub.3 M if R is R.sub.f, PA1 M is typically hydrogen, sodium, potassium, but can be any other counterion such as lithium, calcium, magnesium or an ammonium ion N(R.sub.3).sub.4, where each R.sub.3 may be independently selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, aralkyl or alkaryl group. PA1 R.sub.f is a blend of C.sub.5 F.sub.11, C.sub.7 F.sub.15, C.sub.9 F.sub.19 and C.sub.11 F.sub.23. Most preferred are blends of the above 80/20 blends of betaines and sulfobetaines because such blends of blends have increased solubility in water as well as increased efficiency of reducing surface tension to very low levels at very low concentration if used in combination with Component B.
It is the second property which makes AFFF and AR-AFFF agents far superior to other known fire fighting agents. With AFFF and AR-AFFF agents, the vapor sealing action on non-polar solvents and fuels is achieved by the spreading of the aqueous agent solution draining from the foam onto the non-polar solvent and fuel surfaces, while with AR-AFFF agents, the vapor sealing action on polar solvents and fuels is achieved by the precipitation of a polymer film from a polymer solution draining from the foam onto the polar solvent surface and the spreading of the aqueous film forming solution, also draining from the AR-AFFF foam, over the surface of the precipitated polymer film.
The criterion necessary to attain spontaneous spreading of two immiscible liquids has been taught by Harkins et al, Journal of American Chemistry, 44, 2665 (1922).
The measure of the tendency for spontaneous spreading of an aqueous solution over the surface of non-polar solvents such as hydrocarbons is defined by the spreading coefficient (SC) and can be expressed as follows:
SC.sub.a/b =Y.sub.b -Y.sub.a -Y.sub.i, where PA0 SC.sub.a/b =Spreading coefficient PA0 Y.sub.b =Surface tension of the lower hydrocarbon fuel phase, PA0 Y.sub.a =Surface tension of the upper aqueous phase, PA0 Y.sub.i =Interfacial tension between the aqueous upper phase and the lower hydrocarbon phase. PA0 C.sub.6 F.sub.13 --CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- PA0 C.sub.8 F.sub.17 --CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- PA0 C.sub.5 F.sub.11 --CHF--(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- PA0 R.sub.f --CHF--(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- and R.sub.f --(CH.sub.2).sub.3 --N.sup.+(CH.sub.3).sub.2 --CH.sub.2 COO.sup.- wherein R.sub.f is a mixture of C.sub.5 F.sub.11, C.sub.7 F.sub.15, C.sub.9 F.sub.19 and C.sub.11 F.sub.23 PA0 C.sub.10 F.sub.21 --(CH.sub.2).sub.4 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- PA0 C.sub.8 F.sub.17 --(CH.sub.2).sub.2 --N.sup.+ (C.sub.2 H.sub.5).sub.2 --(CH.sub.2).sub.2 COO.sup.- PA0 C.sub.6 F.sub.13 --(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.3 SO.sub.3.sup.- PA0 C.sub.5 F.sub.11 --(CH.sub.2).sub.3 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.3 SO.sub.3.sup.- PA0 C.sub.5 F.sub.11 --CHF--(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.3 SO.sub.3.sup.- PA0 C.sub.7 F.sub.15 --CHF--(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.4 SO.sub.3.sup.- PA0 R.sub.f --CHF--(CH.sub.2).sub.2 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.3 SO.sub.3.sup.- and R.sub.F --(CH.sub.2).sub.3 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.3).sub.2 SO.sub.3.sup.-, wherein PA0 R.sub.f is a mixture of C.sub.5 F.sub.11, C.sub.7 F.sub.15, C.sub.9 F.sub.19 and C.sub.11 F.sub.23. PA0 C.sub.8 H.sub.17 OSO.sub.3 Na PA0 C.sub.10 H.sub.21 OSO.sub.3 Na PA0 C.sub.12 H.sub.25 OSO.sub.3 Na PA0 C.sub.10 H.sub.21 (OCH.sub.2 CH.sub.2).sub.1 to 3 OSO.sub.3 Na PA0 C.sub.12 H.sub.25 (OCH.sub.2 CH.sub.2).sub.1 to 3 OSO.sub.3 Na PA0 C.sub.12 H.sub.25 --C.sub.6 H.sub.4 --(OCH.sub.2 CH.sub.2).sub.4 OSO.sub.3 Na PA0 C.sub.11 H.sub.23 CON(CH.sub.3)CH.sub.2 CH.sub.2 SO.sub.3 Na PA0 C.sub.11 H.sub.23 OCOCH.sub.2 CH(SO.sub.3 Na)COONa PA0 CH.sub.3 (CH.sub.2 CH.sub.2).sub.4-6 COOCH.sub.2 CH.sub.2 SO.sub.3 Na PA0 CH.sub.3 (CH.sub.2 CH.sub.2).sub.4-6 CON(CH.sub.3)CH.sub.2 CH.sub.2 SO.sub.3 Na PA0 CH.sub.3 (CH.sub.2 CH.sub.2).sub.5 CH.sub.2 CONHCH.sub.2 CH.sub.2 OCOCH.sub.2 CH(SO.sub.3 Na)COONa PA0 NaO.sub.3 S--C.sub.10 H.sub.6 --CH.sub.2 --C.sub.10 H.sub.6 --(SO.sub.3 Na)CH.sub.2 --C.sub.10 H.sub.6 --SO.sub.3 Na PA0 C.sub.8 F.sub.17 OSO.sub.3 Na PA0 C.sub.8 F.sub.17 SO.sub.3 K PA0 C.sub.8 F.sub.17 SO.sub.3 NHCH.sub.2 C.sub.6 H.sub.4 SO.sub.3 Na PA0 C.sub.8 F.sub.17 SO.sub.3 NHC.sub.6 H.sub.4 SO.sub.3 H PA0 C.sub.8 F.sub.17 C.sub.2 H.sub.4 SC.sub.2 H.sub.4 CONHC(CH.sub.3).sub.2 CH.sub.2 SO.sub.3 Na PA0 C.sub.10 F.sub.19 OC.sub.6 H.sub.4 SO.sub.3 Na PA0 (CH.sub.3).sub.2 CF(CF.sub.2).sub.4 CONHC.sub.2 H.sub.4 SO.sub.3 Na PA0 C.sub.10 F.sub.21 SO.sub.3 NH.sub.4 PA0 A. 0.5 to 10% by weight of fluorochemical betaines and sulfobetaines of formula R.sub.f --L.sub.1 --N.sup.+ (R.sub.1)(R.sub.2)--(CH.sub.2).sub.m --Q.sup.- ; PA0 B. 1 to 40% by weight of hydrocarbon or fluorochemical anionic sulfates or sulfonates of the formula R--L.sub.2 --Q.sub.2 ; PA0 C. 0 to 40% by weight of amphoteric and non-ionic hydrocarbon surfactant; PA0 D. 0 to 70% by weight of a water miscible solvent; PA0 E. 0 to 3% by weight of fluorochemical synergist; PA0 F. 0 to 3% by weight of a water soluble polymeric film former; PA0 G. 0 to 10% by weight of a polymeric foam stabilizer; PA0 H: 0 to 5% by weight of an electrolyte; PA0 I: Water in an amount to make up the balance of 100%. PA0 R.sub.f --CHF--CH.sub.2 CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- and PA0 R.sub.f --CHF--CH.sub.2 CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 SO.sup.- and PA0 R.sub.f --CHF--CH.sub.2 CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- (80%) PA0 R.sub.f --(CH.sub.2).sub.3 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 COO.sup.- (20%) PA0 R.sub.f --CHF--CH.sub.2 CH.sub.2 --N.sup.+ (CH.sub.3).sub.2 --(CH.sub.2).sub.3 SO.sub.3.sup.- (80%) PA0 R.sub.f --(CH.sub.2).sub.3 --N.sup.+ (CH.sub.3).sub.2 --CH.sub.2 SO.sub.3.sup.- (20% ) PA0 coco fatty betaine PA0 cocoylamidoethyl hydroxethyl carboxymethyl glycine betaine PA0 cocoylamidoammonium sulfonic acid betaine PA0 cetyl betaine (C-type) PA0 C.sub.11 H.sub.23 CONN(CH.sub.3).sub.2 CHOHCH.sub.3 ##STR2## A coco-derivative of the above Coco Betaine PA0 C.sub.12-14 H.sub.25-29 .sup.+NH.sub.2 CH.sub.2 CH.sub.2 COO.sup.- ##STR3## PA0 Octylphenol (EO).sub.9,10 PA0 Octylphenol (EO).sub.16 PA0 Octylphenol (EO).sub.30 PA0 Nonylphenol (EO).sub.9,10 PA0 Nonylphenol (EO).sub.12,13 PA0 Lauryl ether (EO).sub.23 PA0 Stearyl ether (EO).sub.10,12 PA0 Sorbitan monolaurate (EO).sub.20 PA0 Dodecylmercaptan (EO).sub.10 PA0 C.sub.11 H.sub.23 CON(C.sub.2 H.sub.4 OH).sub.2 PA0 C.sub.12 H.sub.25 N(CH.sub.3).sub.2 O PA0 EO used in the above formulas means ethylene oxide repeating unit. PA0 C.sub.8 F.sub.17 SO.sub.2 NH.sub.2 PA0 C.sub.8 F.sub.17 SO.sub.2 N(C.sub.2 H.sub.5)CH.sub.2 CHOHCH.sub.2 OH PA0 C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.3)CH.sub.2 CHOHCH.sub.2 OH PA0 C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.2 CH.sub.2 OH).sub.2 PA0 C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.2 CH.sub.2 SH).sub.2 PA0 C.sub.6 F.sub.13 CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 CONHCH.sub.2 OH PA0 C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.3)CH.sub.10 H.sub.20 CH.sub.2 OH PA0 C.sub.7 F.sub.15 CON(C.sub.2 H.sub.5)CH.sub.2 CH.sub.2 OH PA0 CF.sub.3 C.sub.6 F.sub.10 SO.sub.2 N(C.sub.2 H.sub.5)CH.sub.2 CH.sub.2 OH PA0 C.sub.3 F.sub.7 O(C.sub.3 F.sub.6 O).sub.2 CH.sub.2 CON(CH.sub.3)C.sub.3 H.sub.6 OH PA0 C.sub.8 F.sub.17 SO.sub.2 N(C.sub.4 H.sub.9)CH.sub.2 CHOHCH.sub.2 OH PA0 R.sub.f CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 CONHC(CH.sub.3).sub.2 CH.sub.2 SO.sub.3 .cndot.N(CH.sub.3).sub.3 CH.sub.2 CHCHCH.sub.2 SCH.sub.2 CH.sub.R.sub.f PA0 C.sub.10 H.sub.21 OSO.sub.3 .cndot.N(CH.sub.3).sub.3 CH.sub.2 CHOHCH.sub.2 SCH.sub.2 R.sub.f PA0 R.sub.f CH.sub.2 CH.sub.2 SCH.sub.2 CHOHCH.sub.2 N.sup.+ (CH.sub.3).sub.3 PA0 C.sub.8 F.sub.17 SO.sub.2 NHC.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.3 Cl.sup.- PA0 C.sub.8 F.sub.17 SO.sub.2 NHC.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.2 C.sub.2 H.sub.5.sup.- OSO.sub.2 OC.sub.2 H.sub.5 PA0 C.sub.8 F.sub.17 SO.sub.2 NHC.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.3 I.sup. - PA0 C.sub.7 F.sub.15 CONHC.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.3 Cl.sup.- PA0 C.sub.7 F.sub.15 CONHC.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.3 CH.sub.2 C.sub.6 H.sub.5 Cl.sup.- PA0 C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.3)C.sub.3 H.sub.6 N.sup.+ (CH.sub.3).sub.3 I.sup.-
If the SC is positive, an aqueous solution should spread and film formation on top of the hydrocarbon surface should occur. The more positive the SC, the greater the spreading tendency will be. Based on the above equation by Harkins, it is obvious that the most efficient surface tension depressants will yield aqueous film forming solutions having the highest spreading coefficient.
While lowering the interfacial tension will also increase the spreading coefficient, it is desirable not to lower the interfacial tension below 1.0 dyne/cm in order to avoid emulsification of non-polar solvents and fuels.
For example, if a hydrocarbon fuel has a surface tension of 20 dynes/cm and an aqueous solution has a surface tension of 16 dynes/cm and the interfacial tension between the two immiscible liquids is 1.0 dyne/cm, then the spreading coefficient (SC) will be +3 (SC=20-16-1=3) and therefore film formation will occur.
Today's AFFF and AR-AFFF agents contain one or more fluorochemical surfactants providing the desired low surface tension of 15 to 18 dynes/cm, one or more hydrocarbon surfactants, providing the desired interfacial tension of 1 to 5 dynes/cm as well as the desired foam properties such as foam expansion, foam fluidity and foam drainage, fluorochemical synergists to improve the efficiency of fluorochemical surfactants, foam stabilizers, solvents, electrolytes, pH buffers, corrosion inhibitors and the like. In addition to the above components in AFFF agents, AR-AFFF agents contain one or more water-soluble polymers which precipitate on contact with a polar solvent or fuel, providing a protective polymer film at the interface between fuel and the aqueous film forming foam. Many U.S. patents describe the composition of AFFF agents as summarized in U.S. Pat. No. 4,999,119. Additional AFFF agent compositions are also described in U.S. Pat. Nos. 4,420,434; 4,472,286; 5,085,786 and 5,218,021.
Compositions of AR-AFFF agents are described in U.S. Pat. Nos. 4,060,489; 4,149,599; 4,387,032 and 4,999,119. in U.S. Pat. Nos. 4,472,286 and 5,085,786, summaries of the development from the beginning of AFFF agent development in the mid-1960s to today's highly efficient AFFF agents are presented.
During the past 25 years, the efficiency of AFFF agents has been significantly improved with the development of formulations based on more efficient fluorochemical and hydrocarbon surfactants, synergists and other additives. And with the invention of the AR-AFFF agents, truly universal type aqueous film forming foam agents can now fight any type of fuel or solvent fire.
What has not changed during this long development period of AFFF and AR-AFFF agent is the general use of fluorochemical surfactants broadly defined as water-soluble fluoroaliphatic surfactants represented by the formula R.sub.f Q.sub.m Z (U.S. Pat. Nos. 3,562,156 and 3,772,195) and (R.sub.f).sub.n (Q).sub.m Z (U.S. Pat No. 4,795,590) wherein R.sub.f is a fluoroaliphatic radical, Z is a water-solubilizing polar group and Q is a suitable linking group. Because AFFF agents are diluted or proportioned with water, fluorochemical surfactants suitable for AFFF agents were required to be water soluble. Water-solubility of fluorochemical surfactants was defined in U.S. Pat. Nos. 3,562,156 and 3,772,195 in such a way that the combination of the fluoroaliphatic radical and the water solubilizing group be so balanced as to provide a solubility in water at 25.degree. C. of a least 0.01 percent by weight and preferably 0.15 percent, particularly in the case where an aqueous film forming foam concentrate had to be prepared. As shown in the recent U.S. Pat. No. 5,085,786, the definition of water-solubility of fluorochemical surfactants for use in AFFF agents has not changed. Minimum solubility at 25.degree. C. in water is still defined as at least 0.01 percent by weight and preferably at least about 0.05 percent by weight.
Today's AFFF and AR-AFFF agents have to meet different fire performance specifications and do, therefore, have different contents of fluorochemical surfactants and of other components. Solutions, also referred to as premixes, made up from today's commercial AFFF and AR-AFFF agents used to generate aqueous film forming foams have fluorine contents ranging from 0.02 to 0.044 percent, depending on the efficiency of fluorochemical surfactants utilized and depending on required performance specifications. Since fluorochemical surfactants, depending on the structure have fluorine contents in the approximate range of about 40 to 70 percent by weight, the fluorochemical surfactant contents in such AFFF and AR-AFFF solutions or premixes can range from as low as 0.029 to as high as 0.11 percent.
This indicates that the actual solubility of fluorochemical surfactants in water, useful for use in AFFF and AR-AFFF agents has to be approximately 3 to 11 times higher than the minimum water solubility as defined in the above mentioned U.S. patents.
Today's AFFF and AR-AFFF agents are concentrates of the 6%, 3% or 1% type. These agent designations indicate that in the case of a 6% AFFF agent, 6 parts of agent have to be mixed or proportioned with 94 parts of water, while in the case of a 3% AFFF agent, 3 parts of agent have to be mixed with 97 parts of water and in the case of a 1% AFFF agent, 1 part of agent has to be mixed with 99 parts of water in order to obtain agent solutions providing upon aeration aqueous film forming foams. Therefore, a 3% agent is twice as concentrated as a 6% agent and a 1% agent is six times as concentrated as a 6% agent. Therefore, today's 6%, 3% and 1% agents contain 16 or 32 or 99 times higher fluorine contents or fluorochemical surfactant contents than quoted above for agent solutions or premixes.
Water soluble fluorochemical surfactants potentially useful in AFFF and AR-AFFF agents can be of the anionic, cationic, amphoteric or nonionic type. Most important in today's commercial agents are amphoteric fluorochemical surfactants, being compatible with any type of hydrocarbon surfactant, followed by anionic fluorochemical surfactants and nonionic fluorochemical surfactants.
Representative water-soluble amphoteric and anionic fluorochemical surfactants are listed in U.S. Pat. No. 5,085,786, while nonionic fluorochemical surfactants are disclosed in U.S. Pat. No. 5,218,021.
A major effort in the past has been the development of agents which could provide better fire fighting foam performance such as quicker fire control and extinguishment, longer foam life and burnback resistance. Today, in addition to developing AFFF and AR-AFFF agents with improved fire performance it has become more and more important that agents are being developed which generate waste streams which either per se have less of a negative impact on the environment and especially on the aquatic ecosystem and the development of agents which produce waste streams which can readily be treated prior to release into public waste water treatment plants or into the environment, therefore having a reduced negative impact on the environment. This is especially important for agents used at fire fighting test facilities where agent waste streams can readily be collected and treated.